scholarly journals A High Voltage Electrostatic Generator

Nature ◽  
1932 ◽  
Vol 130 (3278) ◽  
pp. 306-306
1939 ◽  
Vol 56 (11) ◽  
pp. 1098-1104 ◽  
Author(s):  
I. A. Getting ◽  
J. B. Fisk ◽  
H. G. Vogt

2018 ◽  
Vol 189 ◽  
pp. 11010
Author(s):  
S. M. A. Motakabber ◽  
M. Wahidur Rahman ◽  
Muhammad Ibn Ibrahimy

This paper proposes a single-phase DC to AC inverter for ESG (electrostatic generators) that may be used in the household’s application. The electrostatic generators were developed a while ago and remained abandoned for a long time. Now, as the modern technology advanced, it’s time to utilize the ESG to power generation. A pulse width modulation (PWM) based high voltage DC to AC inverter is a suitable system for converting the EGS high electrostatic DC voltage into standard 50Hz, 220V(rms) AC. The PWM technique is used to control the inverter switches to create a pulse width modulated bi-phase square wave signal. A lowpass LC filter has been utilized to remove the higher harmonic frequencies and which is capable to reduce the total harmonic distortion (THD) around 3.5%. The proposed model showed the overall system performance in terms of efficiency is 95%. To use ESG, this inverter is an easy and cost-effective electrical device. From the result, it is observed that the output voltage of the proposed inverter is greatly improved compared to the other inverter circuits.


Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 802 ◽  
Author(s):  
Hosam Alharbi ◽  
Muhammad Khalid ◽  
Mohammad Abido

An electrostatic generator is an electromechanical device that produces static charges at high voltage and low current. This technology is mature enough, as it has existed for many centuries. Nevertheless, the working principle of most of the commonly used electrostatic generators is still based on typical mechanical methods, which consequently makes them bulky and limits their controllability on the generated charges, e.g., Van de Graaff generator that uses the friction between two different materials to generate electrostatic charges. In this paper, a novel design of a static electrostatic generator (SEG) is presented based on a completely different idea compared to existing electrostatic generators, which offers several potential benefits. The idea originates from the study of a parallel plates capacitor—for instance, if a voltage is applied to two plates of a capacitor, then according to Gauss’s law, both of the plates must have an equal and opposite charge. Suppose one of the plates has a different geometry, with a shorter length than the other, then the number of the charges on both plates will not be equal. Thus, by manipulating the geometrical area of the device, a different number of charges will be generated on both metal conductors. Therefore, a different number of charges are generated on both conductors; hence, by connecting both conductor plates of the capacitance, excess charges will remain on the device. The proposed idea was assessed with computer simulations using finite element and finite difference methods for a variety of different scenarios to determine the optimal design of the proposed device. The device offers several advantages over traditional electrostatic generators, such as that it can generate either positive or negative charges by merely reversing the polarity of the DC source; additionally, it is very simple, lightweight, and easy to manufacture. In particular, the principal advantage of the proposed device is that it is a static one, and no mechanical movement is required to produce charges. Further, the design is general enough and scalable. The simulation results demonstrate the performance of the proposed device.


Author(s):  
L. D. Ackerman ◽  
S. H. Y. Wei

Mature human dental enamel has presented investigators with several difficulties in ultramicrotomy of specimens for electron microscopy due to its high degree of mineralization. This study explores the possibility of combining ion-milling and high voltage electron microscopy as a means of circumventing the problems of ultramicrotomy.A longitudinal section of an extracted human third molar was ground to a thickness of about 30 um and polarized light micrographs were taken. The specimen was attached to a single hole grid and thinned by argon-ion bombardment at 15° incidence while rotating at 15 rpm. The beam current in each of two guns was 50 μA with an accelerating voltage of 4 kV. A 20 nm carbon coating was evaporated onto the specimen to prevent an electron charge from building up during electron microscopy.


Author(s):  
Lee D. Peachey ◽  
Clara Franzini-Armstrong

The effective study of biological tissues in thick slices of embedded material by high voltage electron microscopy (HVEM) requires highly selective staining of those structures to be visualized so that they are not hidden or obscured by other structures in the image. A tilt pair of micrographs with subsequent stereoscopic viewing can be an important aid in three-dimensional visualization of these images, once an appropriate stain has been found. The peroxidase reaction has been used for this purpose in visualizing the T-system (transverse tubular system) of frog skeletal muscle by HVEM (1). We have found infiltration with lanthanum hydroxide to be particularly useful for three-dimensional visualization of certain aspects of the structure of the T- system in skeletal muscles of the frog. Specifically, lanthanum more completely fills the lumen of the tubules and is denser than the peroxidase reaction product.


Author(s):  
L. E. Thomas ◽  
J. S. Lally ◽  
R. M. Fisher

In addition to improved penetration at high voltage, the characteristics of HVEM images of crystalline materials are changed markedly as a result of many-beam excitation effects. This leads to changes in optimum imaging conditions for dislocations, planar faults, precipitates and other features.Resolution - Because of longer focal lengths and correspondingly larger aberrations, the usual instrument resolution parameter, CS174 λ 374 changes by only a factor of 2 from 100 kV to 1 MV. Since 90% of this change occurs below 500 kV any improvement in “classical” resolution in the MVEM is insignificant. However, as is widely recognized, an improvement in resolution for “thick” specimens (i.e. more than 1000 Å) due to reduced chromatic aberration is very large.


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